William V, Landgrave of Hesse-Kassel (1743-1821), was a German nobleman and a member of the House of Hesse. He ruled Hesse-Kassel from 1751 until 1760 and then again from 1785 until his death. His reign was marked by efforts to modernize the administration and economy of his territory. William V was known for his support of the arts and education, establishing institutions that promoted culture and learning. He was also involved in military affairs, aligning with various European powers during the Napoleonic Wars. His legacy includes contributions to the development of Hesse-Kassel as a significant region in Germany.